From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D6499C4727C for ; Fri, 25 Sep 2020 15:24:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 96FC221D42 for ; Fri, 25 Sep 2020 15:24:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601047456; bh=vUXV7pKRwt7V3p7KWdbxevVSMQRAxrKnjuGDVr6gS4U=; h=References:In-Reply-To:From:Date:Subject:To:Cc:List-ID:From; b=nVi+fdA0j0P/aD/SJySmePjD3DELMzwCfnGoFjkDbx6SuqTcYBRIKaXYtvJxKbygF 3QuIBqWSuPT+TP3pQCX/GRWKZecrdgpw0EOzVVpyGxVqDG3Goegb8q463XF5sfw335 xVQig2bmejBtLh57Tt3/evGSh99qA04mfJh4Aoho= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729312AbgIYPYP (ORCPT ); Fri, 25 Sep 2020 11:24:15 -0400 Received: from mail-oi1-f196.google.com ([209.85.167.196]:37201 "EHLO mail-oi1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728678AbgIYPYP (ORCPT ); Fri, 25 Sep 2020 11:24:15 -0400 Received: by mail-oi1-f196.google.com with SMTP id a3so3170013oib.4; Fri, 25 Sep 2020 08:24:14 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=3pZ+oKMneSbQw+VBTAklpjVM+xZE6n37L3PNMsbYGCk=; b=IS5AJUwbxmqg/SlJ5QJYgUH5jffofCrFFxDsdaNFBrSMR7ZlJ/LPj1Xcietl7Dr2Su ugYrqsRmDCv4F3UExVSL9fnB2oMzH+9js2bOYVcJGSQGVw4dLAc+909ofaeSuQCyIuTO 3U7J2OzeF9zTHOniU8rLjph92h/JfqMltnk0yOqMtDXBCH0rTZrCxSfYrz69UewcoA+Q HqliPkwYsH4EdavbKS1UAjNaQxWV9K7kQgshkSv93BBvhnBnruEQ7J8Ljt0+1l5QL3RB +sN6bQJ/cVX1eRih02EhiD/MkMNeuzc79kt3dsyw8MujhQcLyvNSEHUoOfcQP7iJOn1a YZZQ== X-Gm-Message-State: AOAM531GF0CZ+595OjQ9rnn782bWGlavHuRa+WPIyIfGn7w0eR7gQ0Vm dE6ddzdG+gkl6Q/VDieW0E8YE953ctZom6tli+8= X-Google-Smtp-Source: ABdhPJynZTdx2wxg22Twifp6xQ8/oH+tTUIQpiZntiGs7FXznEMy9Km6ptDPDqbUp9ofVaK9Gu8Txi1IadhRpLqTS0E= X-Received: by 2002:aca:5b09:: with SMTP id p9mr568875oib.68.1601047454038; Fri, 25 Sep 2020 08:24:14 -0700 (PDT) MIME-Version: 1.0 References: <20200915103157.345404192@infradead.org> <20200915103806.479637218@infradead.org> <20200925152000.GA171076@roeck-us.net> In-Reply-To: <20200925152000.GA171076@roeck-us.net> From: "Rafael J. Wysocki" Date: Fri, 25 Sep 2020 17:24:03 +0200 Message-ID: Subject: Re: [RFC][PATCH 4/4] acpi: Take over RCU-idle for C3-BM idle To: Guenter Roeck Cc: Peter Zijlstra , "Rafael J. Wysocki" , Borislav Petkov , "the arch/x86 maintainers" , Tony Luck , Len Brown , Daniel Lezcano , Linux Kernel Mailing List , ACPI Devel Maling List , Linux PM , Ulf Hansson , "Paul E. McKenney" , Thomas Gleixner , Naresh Kamboju Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Sep 25, 2020 at 5:20 PM Guenter Roeck wrote: > > On Tue, Sep 15, 2020 at 12:32:01PM +0200, Peter Zijlstra wrote: > > The C3 BusMaster idle code takes lock in a number of places, some deep > > inside the ACPI code. Instead of wrapping it all in RCU_NONIDLE, have > > the driver take over RCU-idle duty and avoid flipping RCU state back > > and forth a lot. > > > > ( by marking 'C3 && bm_check' as RCU_IDLE, we _must_ call enter_bm() for > > that combination, otherwise we'll loose RCU-idle, this requires > > shuffling some code around ) > > > > Signed-off-by: Peter Zijlstra (Intel) > > ia64:defconfig: > > ERROR: modpost: "rcu_idle_enter" [drivers/acpi/processor.ko] undefined! > ERROR: modpost: "rcu_idle_exit" [drivers/acpi/processor.ko] undefined! > > I realize that this has already been reported more than a week ago, with > no visible reaction. Another problem introduced in the same file, resulting > in > > drivers/acpi/processor_idle.c: In function 'lapic_timer_needs_broadcast': > drivers/acpi/processor_idle.c:179:1: warning: > no return statement in function returning non-void > > may cause ia64 boot problems since a non-zero return value will trigger > a function call. AFAICS that is not supposed to happen on ia64. There are fixes for the above in my tree, they will go to Linus shortly. Thanks!